1. Field of the Invention
This invention relates to improvements in oil well pumps and more particularly, but not by way of limitation, to a reciprocal subsurface oil well pump of a minimum length and stroke for an efficient pumping operation.
2. Description of the Prior Art
In producing oil wells it is common practice to provide a pump at the bottom of the well bore, or at least down the well bore in the proximity of the producing formation. The pump is normally secured to the lowermost end of the sucker rod string, which extends longitudinally through the well bore from a reciprocating device at the surface of the ground. The reciprocating device at the surface is usually a horsehead type apparatus and alternately raises and lowers the string of sucker rods in the well bore. Subsurface pumps have long presented problems in lifting of the well fluid to the surface of the ground in that the plunger of the pump is usually several feet long which requires a relatively long stroke for operation of the pump and results in substantially great friction and drag on the pump as the pump plunger reciprocates within the working barrel. As a result, the pump may not move freely and the plunger may not have a full stroke, thus reducing pumping efficiency. In addition, since most of the subsurface pumps are relatively long, it may require several strokes of the pump before a sufficient load is applied to the pump for starting the pumping action. Also, many well fluids contain sand and other foreign particles which greatly hinder the operation of the subsurface pump and frequently damage the working parts thereof.